1. Field of the Invention
The present invention relates generally to a method and apparatus for creating still picture management data on a rewritable storage media, and more particularly, but not by way of limitation, to a method and apparatus capable of reducing the amount of navigation information and index information needed to record still pictures on a rewritable storage media.
2. Brief Description of the Related Art
Currently, a great number of optical disks are being used in various fields. With the advent of the DVD (Digital Versatile Disc), it is expected that more and more optical disks will come into use. Optical disks currently include read-only disks such as the CD-ROM and DVD-ROM and record-once disks such as the CD-R and DVD-R. In addition, specifications for rewritable optical disks such as the CD-RW, DVD-RAM, and so forth are now under discussion.
Since rewritable optical disks like the DVD-RAM have very large capacity, they can store a good many moving/still images. When moving/still images are recorded on a rewritable storage media, information for search and retrieval of the images is created and recorded in a navigation information file on the storage media.
The structure of the navigation information file is shown in FIG. 1, wherein the VOB (Video Object) information field and cell information field are created and inserted in the navigation information file, each time a moving or still image is recorded on the storage media. When reproducing images, the navigation information file is loaded into a memory, and a requested moving or still image is searched for and reproduced from the storage media based on the navigation information.
Since still pictures are much smaller in size than moving pictures, a large number of still pictures can be recorded in a storage media—for example, a 4.7 GB storage media can store more than 60 thousand still pictures. Therefore, when a high-capacity storage media is filled with only still pictures, the amount of necessary navigation information increases relative to the stored still images. When a still picture or audio data linked to the still picture is recorded, the two information fields in FIG. 1 (i.e., VOB information and cell information (CI) fields) take up 84 bytes (e.g., S_VOB (36 bytes)+Cell (2×24 bytes)) including the reserved area. In the above example, therefore, the size of the two information fields needed to store 60 thousand still pictures is 5040 KB (84×60000). FIG. 2 shows the relation between VOB information and cell information created when still pictures are recorded.
As a result, even when limited to storage of still pictures, the size of the navigation information file in a storage media exceeds 5 MB. As mentioned above, the navigation information file needs to be loaded into a memory and searched to locate and retrieve a requested still picture from the media; hence a large memory is required merely to store the navigation information temporarily. If the size of the memory is limited, for example less than 512 Kbytes, the number of still pictures to be recorded should also be limited despite the large capacity of the storage media, which is a major problem of the conventional still picture management method.